Most studies focus on per- and polyfluoroalkyl substances (PFAS) concentrations in dust or particle phase, leaving PFAS in PM₁ particles in urban areas poorly understood. This study investigated PFAS levels and sources in ambient PM₁ from 94 primary and secondary schools across six cities in the Pearl River Delta (PRD) during October to December 2018. We analyzed 32 PFAS compounds in PM₁, with total PFAS levels at 58.92 pg/m³, ranging from 7.33 to 341.77 pg/m³. Perfluoroalkyl sulfonic acids (PFSAs) dominated (median: 38.85 pg/m³), followed by perfluoroalkyl carboxylic acids (PFCAs, median: 11.92 pg/m³), alternatives (median: 1.24 pg/m³), and perfluoroalkyl acid (PFAA) precursors (median: 0.29 pg/m³). The main source for PFAS was organic synthesis industries (47.91 %). Air masses originated from southern China, the east coast, and the South China Sea. PFAS showed positive correlations with cations and anions. Health risk assessment using estimated daily intake (EDI) and hazard quotient (HQ) found very low inhalation risk (HQ < 1). Our results highlight pollution from local industrial production and the eastern coastal areas as being the primary contributor to airborne PFAS in PRD schools. Elevated PFAS levels in PM₁ present potential health risks, and their interactions with other pollutants in PM₁ reflect their complex origins and behaviors.

Background: The prevalence of human immunodeficiency virus (HIV) is becoming more common among college students in China. However, latest data on the prevalence and correlates of HIV testing among sexually experienced college students is rarely. Methods: An online survey was conducted among college students aged 18 years or older using multistage stratified cluster sampling from 16 colleges. Data on socio-demographic, HIV testing, HIV-related awareness, attitudes, sexual education and behaviors were collected. Propensity score matching (PSM) and logistic regression model were used to identify factors associated with HIV testing. Result: A total of 108,987 students participated the survey, of which 13,201 sexually experienced college students were included in this study. 1,939 (14.69%) college students with sexual experience reported uptake of HIV testing in the preceding year. The uptake of HIV testing increased for college students with a rising HIV knowledge score and sexual health knowledge. Being awareness of HIV-related knowledge (aOR = 1.15, 95%CI: 1.01–1.30), accepting one-night stands (aOR = 1.16, 95%CI:1.03–1.32), obtaining satisfactory sexual interpretation from parent(s) (aOR = 1.24, 95%CI: 1.07–1.43), ever had unintended pregnancy (aOR = 1.78, 95%CI: 1.32–2.38), ever had received HIV-related preventive service(s) (aOR = 1.37, 95%CI: 1.10–1.70), ever had participated HIV-related preventive services (aOR = 3.76, 95%CI: 2.99–4.75) and ever had anal sex (aOR = 2.66, 95%CI: 2.11–3.34) were positively associated with uptake of HIV testing. However, accepting premarital sex (aOR = 0.76, 95%CI: 0.66–0.88), accepting cohabitation (aOR = 0.75, 95%CI: 0.61–0.92), occasionally discussing sex with parent(s) (aOR = 0.68, 95%CI: 0.50–0.91), and being with moderate satisfaction of school sex courses (aOR = 0.74, 95%CI: 0.58–0.95) were negatively associated with uptake of HIV testing. Conclusion: The prevalence of HIV testing was relatively low. Participation in HIV-related services and high-risk sexual behaviors were important enablers for testing. Improving sex education for students, increasing HIV preventive services on campus, and improving family sex education are necessary to increase HIV testing among college sexually experienced students.

Background: Human adenoviruses (HAdV) have been known to cause a range of diseases, including respiratory tract infections (RTIs). However, there is limited information available regarding the genotype diversity and epidemiology of HAdV associated with RTIs in Nanning.Methods: Between June 2019 and December 2021, throat swab, nasal swab, or nasopharyngeal swab samples were obtained from individuals hospitalized with respiratory tract infections (RTIs). Statistical software was used to analyze the epidemiological data. The highly conserved 132-bp gene region of the HAdV hexon was targeted for the detection of HAdV using a qPCR assay. An 875-bp hexon gene fragment was subjected to phylogenetic analysis.Results: Significant variations were observed in the age and gender distribution of HAdV-positive patients (P = 0.004 and P = 0.025, respectively). The age distribution of HAdV-positive patients showed that 67.89% of those who tested positive were the age group of 0–6 years. Furthermore, the prevalence of HAdV detection was highest during spring and autumn, with a peak in February. Additionally, genotyping of the 36 HAdV-positive samples with 875-bp fragments identified the presence of circulating HAdV species B, C, and E in Nanning between 2019 and 2021.Conclusions: This study identified an association between HAdV prevalence and age as well as season. Among hospitalized patients with RTIs in Nanning, HAdV-B, HAdV-C, and HAdV-E were found to be co-circulating. The most commonly detected genotypes were HAdV-C1, HAdV-C6, and HAdV-E4.

Ambient exposure to fine particulate matter (PM_2.5) remains a critical global public health concern; however, the speciation and bioaccessibility mechanisms of particle-bound heavy metals within the lung environment are still insufficiently understood. In particular, the role of soluble and insoluble metal species in simulated lung fluids requires further clarification. Road dust, a major contributor to PM_2.5, contains heavy metals that pose significant inhalation risks, leading to oxidative stress, DNA damage, and systemic toxicity. This study investigated the contamination characteristics, bioaccessibility, pollution level, and speciation of heavy metals in PM_2.5-fractionated road dust (PM_2.5RD) collected from Karachi (a megacity with >27 million inhabitants) and Shikarpur (a medium-sized city of ~0.3 million) in Pakistan. A grid-based sampling approach was applied across four functional zones (residential, school, hospital, and office), yielding 48 samples. Inhalation bioaccessibility was evaluated using artificial lysosomal fluid (ALF; pH 4.5, 37 °C, 24 h), revealing moderate bioaccessibility of Cr, As, and Pb. Pollution status was assessed using contamination factor (CF), integrated pollution index (IPI), pollution load index (PLI), and potential ecological risk index. Geochemical modeling with PHREEQC 3.0 and Visual MINTEQ 3.1 was employed to simulate metal speciation, release behavior, and mineral saturation states. Overall, this study provides mechanistic insights into speciation-driven toxicity of As, Pb, and Cr in simulated lung environments, offering a scientific basis for improved risk assessment and regulatory strategies for PM_2.5-associated metal exposure.

Hepatitis B virus (HBV) infection remains a major public health concern among pregnant women, with regional disparities in epidemic characteristics that hinder precise prevention of mother-to-child transmission (MTCT). This study aimed to characterize the seroepidemiological profiles of HBV infection and identify its associated influencing factors among pregnant women in Nanning City, providing evidence-based insights for optimizing targeted interventions to block HBV MTCT. A stratified cluster random sampling strategy was adopted to recruit pregnant women receiving routine antenatal care at designated medical institutions across Nanning between October 2024 and May 2025. Standardized face-to-face questionnaires were administered to collect demographic, behavioral, and disease-related data. Venous blood samples were collected for quantitative detection of five serological HBV markers via chemiluminescence immunoassay. The Kruskal–Wallis test was used to compare the geometric mean concentration (GMC) of hepatitis B surface antibody (HBsAb), while the chi-square test was applied to analyze intergroup differences in the seropositivity rates of the five HBV markers. Multivariate unconditional logistic regression models were constructed to explore factors independently associated with seropositivity of hepatitis B surface antigen (HBsAg), HBsAb, and hepatitis B core antibody (HBcAb). A total of 1,935 eligible pregnant women were enrolled. The overall seropositivity rates of HBsAg, HBsAb, hepatitis B e-antigen (HBeAg), hepatitis e-antibody (HBeAb), and HBcAb were 6.98%, 59.48%, 1.50%, 15.50%, and 33.02%, respectively. Seropositivity of HBsAg, HBsAb, HBeAb, and HBcAb exhibited an age-dependent ascending trend, with the lowest rates observed in the 14–19 age group and peak rates in the 40–49 age group. Rural residents presented significantly higher HBsAg and HBeAb seropositivity but lower HBsAb seropositivity compared with urban counterparts. Participants with unknown or no prior HBV vaccination history showed markedly higher seropositivity of HBsAg, HBeAg, HBeAb, and HBcAb, alongside reduced HBsAb positivity, relative to those vaccinated within the past 5 years or ≥5 years prior (all P < 0.001). Furthermore, individuals vaccinated ≥5 years ago demonstrated higher HBV marker seropositivity and lower HBsAb positivity than those vaccinated within 5 years (all P < 0.001). Multivariate logistic regression revealed that advanced maternal age, rural residency, comorbid chronic underlying diseases, and close contact with HBV carriers/patients were independent risk factors for HBsAg seropositivity, whereas prior HBV vaccination exerted a protective effect. Advanced age, higher educational attainment, and HBV vaccination history independently predicted higher odds of HBsAb positivity; rural residency, chronic comorbidities, and non-medical occupational status were risk factors for insufficient HBsAb seroconversion. For HBcAb seropositivity, advanced age, chronic underlying diseases, and exposure to HBV-infected individuals were independent risk factors, while higher education and vaccination history served as protective factors. HBV prevalence among pregnant women in Nanning exceeds the national average, accompanied by prominent urban–rural disparities. Advanced maternal age and the presence of chronic comorbidities increase HBV infection vulnerability, while vaccination coverage among childbearing-age women remains suboptimal with progressive attenuation of protective antibody titers over time. We recommend targeted booster HBV vaccination for childbearing-age women with insufficient HBsAb levels to curb incident HBV infections and mitigate the risk of vertical transmission.